Hard butter including cocoa butter is widely used in foods such as confectionery products involving chocolates and bread products, pharmaceutical products, cosmetics, or the like. The above hard butter consists primarily of symmetric di-saturated mono-unsaturated triglycerides having one unsaturated bond in a molecule such as 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), a triglyceride having an oleoyl group on the second position and each one group of a palmitoyl group and a stearoyl group (POS), and 1,3-distearoyl-2-oleoyl-glycerol (SOS). Such hard butter is known as tempering fats for chocolates. Further, symmetric di-saturated mono-unsaturated triglycerides having two unsaturated bonds in a molecule such as 1,3-distearoyl-2-linoleoyl glycerol (SLS) which have good quality as a chocolate tempering agent are also known.
Generally, these triglycerides can be obtained as natural fats and oils containing such compound(s), e.g. palm oil, shea butter, sal butter, and illipe butter; or as fractionated oils thereof. Further, other than the triglycerides obtained as fractionated oil of fats and oils such as palm oil, shea butter, sal butter, and illipe butter, it is proposed that such triglycerides can also be obtained by the method which comprises the steps of reacting 1,3-selective lipase to a specific fat or oil; and transesterifying them to produce the triglycerides (Patent Literatures 1 to 3).
In each of the above methods, fractionation is conducted to obtain an end product. However, in order to improve the quality thereof, solvent fractionation or complicated process control is required, and therefore, the above methods are not satisfactory in terms of production efficiency.
Patent Literature 4 discloses a method for producing hard butter without a fractionation process which comprises multistage transesterification comprising the steps of reacting 1,3-selective lipase to a mixture of glyceride fats and oils rich in unsaturated fatty acids on the second position and a fatty acid ester rich in saturated fatty acids and/or a free fatty acid to obtain a reactant; distilling the reactant to obtain a distillation residue wherefrom a part or all of the fatty acid ester and/or the free fatty acid is collected; and repeating the processes of mixing a fatty acid ester rich in saturated fatty acids and/or a free fatty acid to the distillation residue and reacting 1,3-selective lipase thereto. However, by the transesterification, a XXX triglyceride and a XX diglyceride are actually produced as by-products in amounts which cannot be ignored in terms of the quality of hard butter. Thus, it is difficult to produce a tempering cocoa butter equivalent by a multistage transesterification process only.
Patent Literature 1: JP 55-71797 A
Patent Literature 2: JP 62-155048 A
Patent Literature 3: WO 2005/063952
Patent Literature 4: WO 2003/000832